This invention relates to novel surface active compounds having a polymerizable allyl or methallyl group which are particularly useful as an emulsifier in the emulsion or suspension polymerization of various monomers to produce an aqueous suspension of polymer particles.
A variety of surfactants having emulsifying, dispersing, detergent, wetting, foaming and other properties have been used in various products including textile materials, rubber and plastic products, pesticides, metals, paints, pigments, construction materials and the like while utilizing such properties. Recently, active efforts have been made to obtain better acceptance of such products among end users by using a suitable surfactant. As a result of such activities, certain defects associated with the use of conventional surfactant have be revealed.
For instance, the use of certain surfactants is indispensable for the manufacture, stabilizing or workability of paints, printing inks, adhesives and the like. After these products have been used in painting, printing, bonding or other applications, not only is the presence of such surfactants not necessary but often adversely affects the water resistance, oil resistance or other properties of the resultant films or layers. As a countermeasure of these problems, various approaches have been studied including the reduction of the quantity of surfactant or the use of a surfactant having a large molecular weight. However, they are not compatible with the storage stability and/or workability of products to be imparted by the surfactant.
Surfactants are used in the emulsion- or suspension polymerization of monomers for the production of water-based polymer emulsions or suspensions. Examples of surfactants which have been used today for such application include anionic surfactants such as alkyl sulfates, alkylbenzenesulfonates, dialkylsulfosuccinates and polyoxyalkylene alkyl (or aryl) ether sulfates; and nonionic surfactants such as polyoxyalkylene alkyl (or aryl) ethers, polyoxyethylenepolyoxypropylene block copolymers and polyoxyethylenesorbitan fatty acid esters. These surfactants may be used either singly or in combination. However, polymer emulsions and films formed therefrom including these conventional surfactants are far from complete satisfaction with respect to emulsion stabilities and film properties. Thus, many problems still remain unsolved including the polymerization, mechanical, chemical, freeze and storage stabilities and the pigment dispersing property of resultant polymer emulsions incorporating conventional emulsifiers. When films are formed from these polymer emulsions, the water resistance and adhesion thereof are often impaired by the presence of unbound surfactants in the films. When these emulsions are destroyed by means of, for example, salting out to recover polymer particles therefrom, a large amount of waste liquid containing the surfactant are necessarily formed as a by-product. For environmental reasons, this liquid must be subjected to expensive and complicated on-site water-treating processes before it can be disposed as effluent.
A number of patent documents discloses a novel type of surfactants which are polymerizable, degradable or otherwise reactive during or after use so as to be free from the foregoing defects. Examples of Japanese patent documents describing reactive anionic surfactants are listed as follows: Patent Application Nos. 46-12472, 46-34894, 49-46291, 56-29657, and Laid Open Application 51-30285, 54-14431, and 56-127697. Examples of Japanese patent documents describing reactive nonionic surfactants include Laid Open Applications Nos. 50-98484 and 56-28208.
Such reactive surfactants are mainly used in the emulsion polymerization of various monomers but they are not fully satisfactory in the practical application for such uses. One reason therefor is the fact that they are too expensive due to low yields or expensive starting materials. Another reason is that their properties such as emulsifying and dispersing capacities are less than those of conventional surfactants. Finally, despite the presence of a polymerizable moiety, they are not fully suited for such uses.